title: Spin wave excitations of a magnetic pillar with dipolar coupling between the layers.
abstract: It is demonstrated analytically that the spectrum of small-amplitude spatially uniform magnetization excitations in an in-plane magnetized magnetic pillar with two ferromagnetic layers coupled by dipole-dipole interaction can be approximately described by the traditional Kittel formula with reduced saturation magnetization and effective anisotropy field. The spectrum consists of a quasi-symmetric and a quasi-antisymmetric mode, and the apparent reduction of saturation magnetization for the quasi-symmetric mode (≤50%) is much larger than that for the quasi-antisymmetric mode (≤10%). The effect of dynamic dipolar coupling between the nano-pillar layers could be partly responsible for the apparent reduction of static magnetization seen in many spin-torque experiments performed on magnetic nano-pillars.
authors.affiliation: Department of Physics, Oakland University, Rochester, MI 48309, USA.
authors.forename: O
authors.initials: O
authors.lastname: Dmytriiev
authors.forename: T
authors.initials: T
authors.lastname: Meitzler
authors.forename: E
authors.initials: E
authors.lastname: Bankowski
authors.forename: A
authors.initials: A
authors.lastname: Slavin
authors.forename: V
authors.initials: V
authors.lastname: Tiberkevich